3,159 research outputs found

    Hydrodynamic modelling of hydrostatic magnesium extrusion

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    Wilson’s hydrodynamic model of the hydrostatic extrusion process is extended to meet the geometry found on residual billets. The transition from inlet\ud to work zone of the process is not considered sharp as in the model of Wilson but as a rounded edge, modelled by a parabolic function. It is shown that\ud this rounded edge has a considerable influence on the predicted film thickness. Furthermore, it is shown that for hydrostatic extrusion of magnesium with castor oil as pressure medium, it is not possible to generate full film lubrication in the work zone of the hydrostatic extrusion process

    Finding the attractor of anger: Bridging the gap between dynamic concepts and empirical data

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    Although it accounts for the prototypical course of emotions, the attractor concept has hardly ever been used empirically. Authors applied Empirical Differential Equations (EDE) to frequent (hourly) anger ratings to find the attractor of anger. The attractor concept, its neurological basis, and EDE are explained. The attractor of anger follows an underdamped oscillator, and is affected by the capacity to inhibit prepotent responses. Anger accelerates less fast when inhibitory control increases. Results stress the internal dynamics of emotions, and help to bridge the gap between concepts from dynamic systems theory and empirical dat

    Modeling of repeated rolling contact of rigid ball on rough surface: residual stress and plastic strain analysis

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    In this paper, a three-dimensional finite element model of rigid hemisphere repeatedly rolling over a rough flat surface under constant normal load is discussed. The aim of this research is to study the von Mises residual stress and plastic strain distribution and to determine the steady-state phase of the repeated rolling contacts. The results show that the change of residual stress distribution takes place in the first-two rolling cycles and there is no significant change for the residual stress from the second to third rolling cycle, i.e. the surface is run-in after a few cycles. The increase of the contact load affects the area of the von Mises residual stress at the surface and subsurface and also the number of the deforming asperities. The residual stress distribution is getting wider as the normal force increases. The plastic strain is captured after the third cycle of rolling. Small area of plastic strain is found for the rough surface for the low forces applied which indicates the surface deformed mainly elastically. The rough surface is predicted to be plastically deformed for the highest force applie

    Targeting kidney mesangium by nanoparticles of defined size

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    Nanoparticles are being investigated for numerous medical applications and are showing potential as an emerging class of carriers for drug delivery. Investigations on how the physicochemical properties (e.g., size, surface charge, shape, and density of targeting ligands) of nanoparticles enable their ability to overcome biological barriers and reach designated cellular destinations in sufficient amounts to elicit biological efficacy are of interest. Despite proven success in nanoparticle accumulation at cellular locations and occurrence of downstream therapeutic effects (e.g., target gene inhibition) in a selected few organs such as tumor and liver, reports on effective delivery of engineered nanoparticles to other organs still remain scarce. Here, we show that nanoparticles of ~75 ± 25-nm diameters target the mesangium of the kidney. These data show the effects of particle diameter on targeting the mesangium of the kidney. Because many diseases originate from this area of the kidney, our findings establish design criteria for constructing nanoparticle-based therapeutics for targeting diseases that involve the mesangium of the kidney

    MODEX: Laboratory experiment exploring sediment spreading of a mound under waves and currents

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    The dispersal of sand from submerged mounds in the nearshore is driven by the interplay of processes such as converging and recirculating flows, changing roughness, bed slope effects and wave focusing/refraction. This morphological diffusivity is key to understanding sand bars in shallow seas, tidal inlets, estuaries, and the nearshore response to human interventions such as nourishments and dredging. Most of the work on the evolution of submerged mounds has been based on fluvial studies, focusing on flow without waves. In these cases, circular mounds tend to deform to crescentic (barchan) shapes. In contrast, observations of sandbars and berms in the nearshore subjected to waves show much more complex translation and deformation behavior. This contribution introduces the laboratory MOrphological Diffusivity Experiment (MODEX) aimed at examining morphological diffusivity under different forcing conditions. The experiment particularly addresses the linkages between small scale (local) effects (e.g. bed slope, bedforms) on the adjustment of sandy mounds.Peer ReviewedPostprint (published version

    Экзистенциальный базис сущностных сред

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    Создается экзистенциальная платформа дескриптивных сред. На ее основе строятся модели информатико-технологических систем. Проводится прагматико-обусловленная типизация универсума компаундов. Раскрывается компа- ундная природа средств квантификации и суперпозиции функций.Створюється екзистенційна платформа дескриптивних середовищ. На її основі будуються логіко-математичні моделі інформатико-технологічних систем. Проводиться прагматико обумовлена типізація універсуму компаундів. Розглядається компаундна природа засобів квантифікації та суперпозиції функційAn existential platform of descriptive environments has been created, on the basis of which logic-mathematical models of informative technological systems are built. A pragmatically conditioned typification of the universal set of compounds is performed. The compound nature of the means of quantification and superposition of function is discussed

    Broken Symmetry in Density-Functional Theory: Analysis and Cure

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    We present a detailed analysis of the broken-symmetry mean-field solutions using a four-electron rectangular quantum dot as a model system. Comparisons of the density-functional theory predictions with the exact ones show that the symmetry breaking results from the single-configuration wave function used in the mean-field approach. As a general cure we present a scheme that systematically incorporates several configurations into the density-functional theory and restores the symmetry. This cure is easily applicable to any density-functional approach.Comment: 4 pages, 4 figures, submitted to PR
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